By David Tanner, Land Line associate editor | Friday, November 01, 2013

U.S. federal agencies that are pursuing a mandate for speed limiters on heavy trucks are doing so without real-world data on speed limiters or on whether the devices would make a difference in road safety.

The revelation comes with the release of the latest crash data in late October by the National Highway Traffic Safety Administration, specifically the sections that deal with fatality and injury crashes involving large trucks.

The latest complete stats, which are for the year 2011, show that speeding-related factors were the most common cited in fatality or injury crashes that involved large trucks.

Specifically, 283 fatal crashes involving a large truck had a speed-related factor. However, that does not necessarily mean the truck driver was speeding. The catch-all term of “speeding related” actually tracks seven different violations of the safety regs.

“Speeding related” includes violations of speeding as defined in 392.2: speeding 6 to 10 mph over; 11 to 14 mph over; 15 or more over; and speeding in work/construction zone. It also includes violations of failure to use caution for hazardous conditions (commonly referred to as driving too fast for conditions) and using or equipping a CMV with a radar detector.

When that stat is broken down a bit, 82 percent of fatal crashes involving a large truck occurred on roads with posted speed limits at or lower than 65 mph. The highest percentage of speed-related crashes involving a large truck occurred on roadways with a posted speed limit between 50 and 55 mph.

How many of the trucks involved in those fatal crashes were equipped with an activated speed limiter? Land Line posed the question to NHTSA, and received a response.

“The agency does not have crash data related to activated speed limiters in our databases,” a NHTSA communication spokesman said.

The agency, partnering with the Federal Motor Carrier Safety Administration as part of a joint proposal to mandate speed limiters on heavy trucks, is instead relying on a 2012 study that showed a “safety benefit” to speed limiters. More on that study later.

BackgroundIn 2006, the American Trucking Associations and Roadsafe America petitioned NHTSA and the FMCSA to pursue a rulemaking to mandate speed limiters on heavy trucks. The groups asked for a 65 mph cap on road speed.

NHTSA, on its own, granted the petition in 2011 and began drafting a proposal. FMCSA rejoined NHTSA in May of this year to pursue the proposal jointly. The agencies recently targeted a date of Nov. 20 to advance the proposal to the Office of Management and Budget. The recent government shutdown may or may not affect that advancement.

“Based on the available safety data and the ancillary benefit of reduced fuel consumption, this rulemaking would consider a new Federal Motor Vehicle Safety Standard that would require the installation of speed-limiting devices on heavy trucks,” the agencies state in abstract information available online. “This rule would decrease the estimated 1,115 fatal crashes annually involving vehicles with a (gross vehicle weight) of over 11,793 kilograms (26,000 lbs) on roads with posted speed limits of 55 mph or above.”

Available safety data questionedOOIDA is not the only one that calls into question the current available safety data about speed limiters that the FMCSA has published via a study of motor carriers in 2012.

One comparison in the study compared less-than-truckload fleets equipped with speed limiters with long-haulers that were not equipped with speed limiters. One of the long-haulers in the study possessed a crash rating three times higher than the other fleets in the study.

The study used a measure of “accidents per 100 truck-years” instead of using vehicle-miles traveled as the preferred comparison. Most transportation studies in the academic community use VMT as the yardstick.

And while the final draft of the FMCSA-commissioned study showed a “strong safety benefit” for speed limiters, a previous draft of the study a year earlier showed “no clear benefit.”

The difference in findings caused a researcher who worked on the study, Steven Johnson of the Mack-Blackwell Transportation Institute at the University of Arkansas, to distance himself from the findings and write a rebuttal about the way the data was interpreted by the other authors.

Johnson has shown in previous studies about speed differentials on rural interstates that vehicles traveling at different speeds will interact more than vehicles traveling at uniform speeds.

OOIDA takes the same position on uniform speed as a matter of highway safety, often citing Johnson’s studies on the subject.

The Association says the pursuit of speed limiters as a trucking industry mandate is a misguided approach.

“Putting a speed-limiter mandate out there without showing the real-world impacts to safety is a real sign of what’s wrong with our regulatory system,” said OOIDA Director of Government Affairs Ryan Bowley.

OOIDA points to the relatively low number of crashes on roads in which speed limiters would make a difference. And even then, there’s no guarantee that a speed limiter would prevent a crash from occurring.

“Speeding-related crashes on higher-speed roads like interstates and freeways, the very places where a speed limiter would control truck speeds, represent less than 4 percent of all fatal truck-involved crashes and less than 0.3 percent of all fatal crashes,” OOIDA says. “And there is no proof that a speed limiter would have prevented even these crashes.”

AlternativesOOIDA supports efforts to train entry level truck drivers and equip them with the knowledge they need about their vehicles and highway safety.

The Association launched a safety agenda earlier this year that targets driver training.

The majority of crashes involving large trucks also involve a passenger vehicle driving unsafely or speeding. Therefore, OOIDA supports an approach that addresses passenger vehicle drivers.

“If anything, they should be doing more to address passenger cars driving unsafely and speeding around trucks, and causing truck-involved crashes that way,” Bowley says.

“That’s certainly what we’ve seen when law enforcement has done targeted speeding enforcement action – that it’s the cars that are speeding, that the cars that are cutting off trucks, and that 80 percent of the truck-involved accidents are the fault of the driver of the other vehicle, not the truck driver.”